Recoil brake



H. B. MARIS July 2, 1946-.

Filed ,Feb. 23, 1945 INVENTOR. HARRY B. MARIS" FIG Patented July 2, 1946UNITED STATES o -"icef;

= 2,403,061-Q meta nrtinnfj Harry B; Maris, Rivrdale Md. ApplicationFebruary 23, 1943, Sara; No. 476,857

2 3lairns.. (01. 89-14) (Granted under the act of March '3, 1883, asamended April -30, 1928; 370-0. G. 757) i This invention is a recoilbrake for firearms.

It may also be termed a compensator.

It is adapted to be secured to the muzzle'of a standard firearm, and tobe removable therefrom,

although it may be made an integral part of I the same.

One object of the invention is to produce a novel construction for themuzzle of a gun,' which will reduce the recoil associated with firing.

Another object of the invention is to provide a one-piece recoil brakeor compensator which is easy to manufacture and of great mechanicalstrength, and which will increase the efiective length of the barrel ofthe gun.

Another object is to produce a recoil brake which will function also toeliminate the flash of the gun. i

An additional object is to produce a recoil brake which will reduce oreliminatethe sound of gunfire.

vide in a brake of the nature mentioned; for expansion and slow escapeof most of the gases of an explosion, while at the same time to utilizea part of the gases to maintain pressure behind the projectile beingfired.

Other objects will be apparent from a reading: of the followingspecification and claims. In the drawing, Figure 1 is a section takenaxially through the bore of the compensator. and a portion of a riflebarrel associated therewith, Figure 2 is a section through the expansionand escape chamber of the compensator on the plane indicated by line 2-2of Figure 1 (and indicating by the line l-! the exact plane of thesection of Figure 1), Figure 3 is a perspective-view of the principalportion of the recoil brake; and

Figure 4 is a section on a plane similar tothat of Figure 2, butillustrating a modification of the invention.

mferring to the drawing, and especially to Figure 1, l represents thebarrel of the gun,

which may be assumed to be a .50 machine gun. The bore of the gun isrifled, as indicated at H. The muzzle of the piece is provided withthreads I2.

The recoil brake proper, I3, is securedtto thebarrel ID of the gun bymeans of threads cooperating with threads l2 on the gun muzzle. And,-

in departure from previous practice-which has been to make the brakebore large enough to prevent the projectile from touching the same whilepassing therethrough-the bore of this invention is precisely the same asthe caliber of the gun to which it is attached, and it contains riflingI4 It is a further object of the invention to prowhich is to beaccurately matched to the rifiing' H's-in the gun barrel. 'A set screwl5,lor. some other means,'must be: provided fonmaintainin'g the gunbarrel and the compensator in proper relation as regards rifling.Passageways forming expansion chambers are The I external appearanceofthese'chambers isbest illustrated provided for the escaping gases.

in Figure 3.

The internal formation of the expansion 'chame hers is shown inFigure 1. Communicating with the bore of 'thebrake are slot-likeopenings which" permitescape of :thel gases from thebore; Two' suchopenings, 2| and 22, are shown in full in Figure 1, Two others, 20 and23, are shown in part. Openings 24 and 25 are indicated in Figure 2.*Thezexact size of these openings will vary inversely with the length ofthe brake.

. Extending'radially outwardly from the slot-like openings are theexpansion chambers proper of the brake; The chamber at the right ofFigure l willxbezdescribed in detail. The other chambers aresimilar. P 4In'ithebody portion of the compensator, and extending forwardly from theforward end of slot 23*:is .formed a curvedsurface '26,;the, curve ofwhich reverses at 21 as it approaches the peripheryiof the enlargedportion of the brake. The surface 26 functions to receive thehigh-velocity escaping gases; and to change their direction from"forward to. rearward .and outward." The' rear. wardly directed gasesimpingeonra substantially fiat surface 28, and from thence, pass to theouter air. 1 The reverse. curve 21 tends to reduce the.

blast efiect on the gunnen;

Ihe vexact angle of the face or surface 28is a matter of. compromise.

on the line 22 of Fig. 1. From the standpoint of recoil elimination, itis desirable to makethis angle as great as possible, but ifit bemademuch:

greater than 45, the escaping gasesjbecomera discomfort and possibly adanger to the gunner."

The shapes of the remaining sides of theexpansionchamber are determinedby the vanes 30, 3|, .32, 33, 34 and 35 (see Figures 2 and-3). Thesevanes extend: radially outwardly from the surface of ,the brake'borerand terminate in longitudinal edges aligning withzthe cylindricalSexterior. surface ofthe compensator Wherebylaterally.expandingugasesescaping from the -pas-'- sageways smoothly merge at theperiphery of 'the compensator. In contradistinction to somecompensators, wherein the parts are formed expressly to produce aturbulent condition to aid in cooling It is shown as being aboutrelative'to a vradial plane substantially;

in order to permit great expansion of the gases The ratio can beforethey reach the outer air.

be made virtually as great as desired-by increas ing the diameter of thebrake; in the structure shown, 20 or 30 to 1 can readily be obtained,and this is ordinarily more than suificient. A ratio of at least 15 to 1will in most instances .be. satisfactory.

Figure 4 illustrates a modified vane structure for the recoil brake ofthe invention. The curved 5 ribs or vanes 40, 4|, 42, 43, 44 and 45provide longer paths for the hot gases before they reach theexterior. ofthe brake, and thus a larger tem-. perature drop. Further, they produce,or tend to produce, an eddying or turbulent condition outside of thebrake; as in the form. earlier described, no turbulence is sought insideof the compensator. r

. The structure of Figure 4 has an additional useful and novel property.By proper disposition of the vanes with respect to the direction of therifling of the firearm, the reaction of the escaping.

gases on the curved vanes is. caused to produce a moment to counteractor resist any twisting effect in the barrel resulting from the rotationof a projectile passing therethrough.

Modification of the vane construction, in accordance with Figure 4, doesnot require changes in the remainder of the brake.

In operation, as a bullet passes the rearward limits of openings 28, 2|,22, 23, 24, and 25, these openings of course permit the escape of someof the gases in the barrel. The parts of the brake are so proportionedas to provide an escape for approximately three-fourths of these hotgases during the time of travel of the projectile between the openingsand the forward end of the recoil brake.

The total area of the openings mentioned is approximately 2 times thearea of the bore. The velocity of the escaping gases is, therefore, morethan doubled, and their pressure correspondingly' reduced.

The velocity of the gases remaining in the bore of the compensator isnot substantially changed, and these remaining gases, notwithstandingtheir reduced quantity, maintain pressure behind the bullet. This effectrequires the substantially pressure-tight relation between bullet andbore which has been mentioned. The duration of the effect is dependentprincipally upon the size of the openings -25 and the length of the boreforward of the openings. If the elements' are correctly proportioned, itis possible to maintain a high pressure in the bore almost to the muzzleof the compensator, and yet provide, before the gases escape behind thebullet, such reduction in temperature and pressure as will virtuallyeliminate the sound and flash of these gases.

With respect to the main escape and expansion chambers and the gasespassing therethrough, the design of the brake should take into accountthe following considerations. The sound of the explosion will bedeadened in proportion to the length of time provided for the escape ofthe gases-the longer the time, the more complete the effect. Performancein this regard thus will vary inversely with the size of the openings inthe bore, and directly with the diameter of the chambers. Elimination ofthe flash of the gun depends upon the extent to which the hot gases arecooled before mixing with the outer air, and

therefore upon the amount of expansion provided for before the gasesreach outer air. In the event all powder grains are not burned when thebullet reaches the outlet openings, the time taken for the combustionproducts to pass through the expansion chambers is a factor.

The above description is in specific terms. It

is apparent that many changes are possible within the spirit bf theinvention, and it is therefore intended not to limit myself to the exactsubject matter shown and described, but instead to include all thatproperly falls within the scope of the appended claims.

This invention may be manufactured and/or used by or for the Governmentof the United States of America without the payment to me of any royaltythereon or therefor.

I claim: a

1. A recoil brake for a gun comprising a onepiece elongate body portionhaving a central longitudinal bore therein adapted to match the bore ofthe gun barrel, said bodyportion including a forward muzzle portion andan enlarged rear vent portion of cylindrical shape and provided'withpassageways from the brake bore to the cylindrical exterior of said ventportion, the' material of the rear vent portion between the passagewaysconstituting substantially streamlined vanes extending radially fromsaid bore to the outer limit of said rear vent portion and terminatingin edges longitudinally aligning with the cylindrical exterior of saidenlarged rear vent portion, the forward wall for each passagewayincluding a forwardly and outwardly curved portion for receivingexplosion gases and the rear wall for each passageway being rearwardlyand outwardly inclined throughout its length, said forward muzzleportion serving to increase the effective length of the gun barrel.

2. A recoil brake for a gun comprising an elongate body portion having abore therein adapted to match the bore of the gun barrel, said body'portion including a forwardmuzzle portion and an enlarged cylindricalrear vent portion provided with radial passageways extending from thebrake bore to the cylindrical exterior of the rear vent portion, thematerial of the body portion between the passageways constitutingsubstantially streamlined vanes extending radially from said. bore andterminating in edges longitudinally aligning with the cylindricalexterior of the rear vent portion, the forward wall for each passagewayincluding a forwardly and p outwardly curved portion for receivingexplosion gases and a rearwardly and outwardly reversely curved portionfor reducing the blast effect toward the" gunner, and the rear wall foreach passageway being rearwardly and outwardly inclined throughout itslength.

HARRY B. ARIs:

